Scattered to fairly widespread rainfall has been reported from parts of peninsular, east and northeast India as the moisture pipeline from the nearby seas sustained during the past 24 hours ending Wednesday morning.

A trough ran north-east from south Konkan coast to Chhattisgarh across Vidarbha with an embedded cyclonic circulation over Chhattisgarh. The cyclonic circulation over south Konkan and Goa also has got embedded into this formation.

This is what has been driving the west session over peninsular, central and east-central India. On Tuesday, it just got extended into the northeast.

CYCLONIC WHIRLS Towards the south, a cyclonic circulation has popped up over south Tamil Nadu and adjoining Kerala. International models traced another cyclonic circulation over southwest Bay of Bengal as well.

This is seen as a precursor to the anticipated easterly wave towards Sri Lanka and southeast Tamil Nadu over the next two days.

The wet phase of the Madden-Julian Oscillation (MJO) wave that oversaw heavy rains over the peninsula, including the formation of Cyclone Phyan, may be exiting but a remnant is still active over the East Indian Ocean.

The Climate Prediction Centre (CPC) of the US National Weather Services sees the alternate dry phase of the MJO wave kicking in over southwest Indian Ocean during November 17 to 23.

This should normally dry up the southern Indian peninsula during the last week of the month, but international models see lingering moisture over land falling as rain in the interim.

A few models also saw the possibility of a remnant of the wet MJO wave to the extreme northwest of the Maritime Continent (Indonesia) triggering some activity over south-central and adjoining central Bay of Bengal. Coastal Tamil Nadu may receive some rains in the bargain, the outlook said.

Leading MJO trackers are of the view that equatorial Indian Ocean will get to see the next wet phase, though comparably weaker, from mid-December onwards.

RAINS FORECAST An update from the Chennai Met Centre said that the 24 hours ending Wednesday morning saw rainfall occur at many places over coastal Andhra Pradesh and Telangana.

A few places over Tamil Nadu, Rayalaseema, coastal, north and south interior Karnataka, and Kerala too, received rainfall of varying amounts.

Forecast for the next two days said that rain or thundershowers are likely to occur at many places over north coastal Andhra Pradesh, Telangana and north interior Karnataka.

Thundershowers have been forecast at a few places over Tamil Nadu, Puducherry, Kerala, Lakshadweep, south coastal Andhra Pradesh, Rayalaseema, coastal and south interior Karnataka.

Outlook from the IMD said that scattered to fairly widespread rainfall activity is likely over the North-East during the next two days and decrease thereafter.

Scattered rainfall has been forecast over peninsular India during the next three days. Isolated to scattered rainfall is likely over east India.

Maximum temperatures are likely to increase by 3 to 4 degree Celsius over central and over plains of northwest India during the next four days. Minimum temperatures may fall during this period.

Moderate fog conditions are likely to prevail over plains of northwest India. A fresh western disturbance is likely to affect the western Himalayan region on Monday.

Widespread to fairly widespread rainfall has been reported from Madhya Pradesh, Chhattisgarh, interior Maharashtra and West Bengal during the 24 hours ending Tuesday morning.

OVERNIGHT RAINS

This came about as westerly and southwesterly winds blowing in from the Arabian Sea acted in tandem with a prevailing western disturbance to empty their baggage of moisture over the region.

An India Meteorological Department (IMD) update said that most places in south interior Karnataka, Madhya Maharashtra, east and west Madhya Pradesh, Vidarbha, Chhattisgarh, Jharkhand and Gangetic West Bengal witnessed overnight rainfall.

Scattered rainfall has been reported also from the west coast, Tamil Nadu, east Uttar Pradesh, the Northeastern States and Jammu and Kashmir.

The rain belt is forecast to progress to further east and northeast during the next few days, according to the IMD. The moisture supply would be intact as a helpful trough extended from south Konkan into Chhattisgarh across south Madhya Pradesh on Tuesday.

The IMD outlook until Friday spoke about the possibility of scattered to fairly widespread rainfall over central India during the next 24 hours and over east India during the next two days. Scattered to fairly widespread rainfall activity has been forecast for the Northeastern States during the next three days.

In this manner, the IMD sees rains to linger over south interior Karnataka, Goa, Madhya Maharashtra, Marathwada, Madhya Pradesh, Vidarbha, Chhattisgarh and the entire Northeastern States over the next few days.

This is in agreement with the outlook of most international weather models, including the US National Centres for Environmental Prediction (NCEP) and the Climate Prediction Centre (CPC) of the US National Weather Services.

A warning valid for the next two days said that isolated heavy rainfall is likely over Assam, Meghalaya and Arunachal Pradesh.

Meanwhile, an update from the Chennai Met Centre said that rainfall occurred at many places over Karnataka and at a few places over Tamil Nadu, coastal Andhra Pradesh and Rayalaseema during the 24 hours ending Tuesday morning. Isolated rainfall occurred over Kerala, Lakshadweep and Telangana.

Outlook until Thursday said that rain or thundershowers are likely at many places over Karnataka and at a few places over Tamil Nadu, Puducherry, Kerala, Lakshadweep and Andhra Pradesh.

A keen watch is now being maintained for an easterly wave that is expected to start impacting Sri Lanka and southern peninsular India in the immediate vicinity from this weekend.

This is because the sea-surface temperatures in the southwest Bay of Bengal and around Sri Lanka have cooled down over the past few days to between 26.7 deg Celsius and 28 deg Celsius which can barely support weather systems for long.

The warmest waters now lie along the Kerala coast, northwest and adjoining central and south-central Bay of Bengal as well as a little further south of Sri Lanka, extending to the west of the Maritime Continent (along the Indonesian coast).

Most international models see the wave setting up some activity around Sri Lanka coast and across into southeast Tamil Nadu coast and adjoining south Kerala.

The system may die out after encountering land features over Sri Lanka and emerging weakened into southeast Arabian Sea. Rain gains are indicated for Sri Lanka and southeast and southwest peninsular India.

The odd model guidance favours a scenario where the system seeks warmer waters to the north i.e. over south-central and adjoining northwest Bay of Bengal waters. It could also undergo a round of intensification in the Bay basin.

An IMD update said that on Tuesday, maximum temperatures were below normal over west Madhya Pradesh, north Madhya Maharashtra, east Uttar Pradesh, Konkan, Goa coast, Rajasthan, Punjab, Haryana, and Bihar by varying margins.

They were above normal over coastal areas of Orissa and north Andhra Pradesh, interior Karnataka, remaining parts of Andhra Pradesh, Orissa and Gangetic West Bengal.

Moderate fog conditions are likely to continue over the plains of northwest India during the next three days, the IMD update said.